Concrete wall structure and method of production



F. P. SLOAN 2,042,487

CONCRETE WALL STRUCTURE AND METHOD OF PRODUCTION June 2, 1936.

Filed Jan. 20, 1934 INVENTOR:

ATTORNEYS.

Patented June 2, 1936 UNITED STATES CONCRETE WALL STRUCTURE AND- METHOD OF PRODUCTION Francis P. Sloan, Scarsdale, N.-Y.

Claims.

This invention is a novel concrete wall structure and the method of production thereof; having particular reference to floor arches, side walls or other concrete wall structures with indoor 5 exposure, wherein the sofiits or other surfaces are so constituted as to diffuse reflections and thereby substantially to destroy sound waves impinging thereon, by absorbing or dissipating the waves, or causing them to be neutralized, so

as to prevent objectionable reflection of sound in the form of echo or reverberation. The construction hereof incidentally aids also in the suppression of sound transmitted through the structure by preventing its effective delivery into the adjacent air. The invention is useful for structures formed at the place of use, but as to some features is also of advantage in the production of preformed slabs, blocks or plates adapted to be erected as or attached upon floor arches, walls or other structures. j

The general object of the present invention is to afford a practical, simple and inexpensive reflection diffusing or sound deadening concrete room-wall which will be highly effective for the purpose, and durable-in use. A further object is to afford such a structure that will present a substantially uniform and decorativeappearance.

Other objects and advantages will-be hereinafter explained or will be manifest to .those conversant with the subject.

In using herein the term wall withoutqualification, it is intended to include not only side walls of enclosures, but other boundary structures, as top walls or ceilings, or bottom walls floor arches, or interior columns.

In carrying out the present invention the characteristics of porous or cellular concrete are taken advantage of, having reference to any type of porous concrete, such as aerated or expanded Portland cement concrete, honeycombed with small cells and therefore light of weight while strong enough for many structural purposes; and by this invention a porous concrete floor arch, Wall, slab or other structure is produced in a form with its surface broken up into a condition or configuration practically ideal for the deadening of impinging sound waves, and diffusion of light waves.

While the method and product of this invention may be described in general terms, the drawing is herewith presented showing, simply as an illustrative example, a method and a product embodying the present invention, it being understood that the embodiments may be variously modified without departing from the principles.

Application January 20, 1934, Serial No. 707,478

For convenience, the principles of the invention will be described in connection with the disclosure illustrated on the drawing, and the drawing is first'described as follows.

Figure 1 may be considered a vertical section through a portion of a building including a portion of an arch or floor, the under side or sofiit 'of which embodies the present invention.

Fig. 2 on a much larger scale than Fig. 1 is'a sectional diagram of a fragmentary portion of the sofiit of the structure or arch, constituting the top wall or ceiling of the apartment beneath.

Fig. 3 is a face view of the surface or product of Figs. 1 and 2, looking from underneath.

Fig. 4 is a sectional view of a modified structure.

Fig. 5 is an elevational view of an implement adapted to carry out the method hereof in one of its forms.

Fig. 6, in elevation, shows a different method of carrying out the invention.

Fig. '7 shows a wall structure in perspective comprising slabs embodying the invention.

In the drawing an upright or room side wall structure A is shown, and extending from one side-thereof an arch or floor structure B constituting a room top wall and containing reinforcing members or rods C. These illustrations are diagrammatic in nature and intended to be representative of any forms or types of=oqncrete arches or other walls. The porous or cellular concrete, whether of the expandedfor'other type, may be-employed to form the wall-or the floor arch in:the usual way. The application" of the invention to the arch will first-be described.-

On Fig. l in dotted lines'is indicatedthe'temporary support member D.:of the farch 'm'old, which may comprise'a smooth surface of'metal or other material mounted as usual somewhat lower than the reinforcements C. Assuming the case of expanded concrete E such concrete will next be poured in semi-liquid or plastic condition upon the support D. The upper surface of the support should be clean and free of foreign matters, and the concrete should be poured to a partial depth, indicated by the line F. The mix should be uniform and without lumps or foreign matters, and preferably comprises as usual sand or other fine aggregate mixed with the Portland cement and water, and the self-expanding agent as aluminum. Thereafter the concrete E is allowed to expand, for example to the full depth G, and will then be allowed to set for the usual time before stripping away the support D. In the case of slabs -or wall members these operations 55 may be performed in a mold and the set slab removed from the mold. The resulting product in any case is a floor arch, wall, slab or other structure of which the surface to be subsequently treated isa practically closed surface or is enclosed by a substantially smooth skin or surface wall H, behind which is a multiplicity of closed empty cells I, that is, containing air or gas but no solids. If there are irregularities in the supporting member D or for other reason the under surface or soillt of the arch is blemished, this invention allows the workman to remove and obliterate the defects and produce a substantially uniform and decorative appearance.

According to this invention the cells or pores adjacent to and covered by the skin or surface wall H are to be opened up and exposed to. the atmosphere and to sound waves impinging upon the surface, namely, by treating as by perforating the skin. By this means the continuity of the outer surface is thoroughly broken up in a most advantageous manner for the suppression of reflection or reverberation. No plane surfaces remain and any sound wave that may be reflected is so diffused as to be substantially destroyed as sound, and partly neutralized, and to some extent absorbed within the concrete, echoes being effectively prevented.

Preferably this invention is carried out. by piercing the skin or surface wall H by numerous punctures entering into the adjacent cells, thus admitting air and sound and light vibrations to the cells, without destroying the cells or the thin separating walls or partitions between the cells. The same results of opening the cells to exposure may be attained in other ways, for example by grinding or shaving off the skin, but the employment of a skin piercing action for this purpose is found to be superior both in procedure and product. It is observed that generally a few cells may accidentally be opened to exposure on removing the support or mold, but not to an extent or uniformity to serve usefully the purposes of this invention, but on the contrary to the detriment of appearance and requiring corrective treatment. The lowermost cells I are to be widely opened up, as inFigs. 1 to 4, 6 and 7 indicated, thus exposing domed cavities of large open diameter, which occupy a large or even a preponderating portion of the entire surface area.

The step of piercing or otherwise treating the skin H to expose the adjacent cells may be performed shortly after the setting of the cellular concrete, or substantially later. Figs. 2 and 3 show the principles of the invention, the cells J which have been exposed or pierced being open to the atmosphere and being separated by thin partitions or wall portions K of the concrete which advantageously should be preserved. This step of exposing the cells by piercing the surface under treatment may. be performed in various ways, for example by means of wire bristles or needles.

In Fig. 5 is shown a piercing implement L carrying a series of fairly stiff wire bristles M spaced well apart, roughly corresponding with the size and spacing of the cells, which implement may be operated by thrusting or poking it against the surface, causing the bristles to pierce and puncture the skin and enter the-cells. The action may be repeated at each area to give the wide open effect seen at the left side of Fig. 2. In some cases the bristles will pass completely through a surface, cell and therebeyond into another cell, while in other cases a bristle may perforate the skin H but meet resistance, the bristle in that case yielding. The operation is such as to preserve'to the maximum the wallsK between the exposed cells J. more so than with a grinding or shaving action. The workman can readily by observation employ the puncturing implement in Another method of exposing the cells adjacent to the skin H is indicated in-Fig. 6 wherein is shown an air blast nozzle N projecting a blast of coarse sand 0 or other material capable of disintegrating the surface H and penetrating into the cells adjacent thereto. The pressure of the air blast should be regulated to control penetration. Adhering particles of the sand or other projected solid are readily removed, as by the use of the bristles hereinbefore mentioned.

The surface having thus been effectively prepared according to this invention, the following supplemental treatments may be performed. Dust and loose matter occupying the exposed cells should be removed and the surface otherwise cleaned. It is advantageous then to harden the concrete where it is exposed to the atmosphere andthis may be effected in any usual manner, as by spraying the material with a fluorsilicate or other hardening agent. Finally, the surface may advantageously be coated with a protective coating, for example a thin paint or lacquer applied or sprayed thinly over the concrete surface, thus rendering it hard and durable. These treatments leave intact the cellular exposed contour, giomprising cavities divided by septums or partions.

When the invention is applied to slabs preformed for subsequent erection in walls or arches, the slabs It may be treated as described, and arranged, for example as shown in Fig. '7, in superposition to constitute the sound deadening face of the wall A. Preferably, however, the slabs will be erected and then treated to expose the cells; this giving greater safety and preservation in handling, also permitting coordinated treatment of a series of slabs embodied in a given wall.

In lieu of mechanical disintegrating or piercing of the skin for exposing the air cells adjacent to the surface being treated, this result may be achievedin radically different ways. For example, sugar or similar agent, may be applied to the top surface of the support D, this agent acting to destroy the cohesion ofthe cement or to prevent the hardening or completion of the setting thereof, so that when the support is removed the skin will readily become detached or crumble from the surface, leaving the cells exposed as desired; after which the surface will preferably be touched up by the bristle implement or other methods described.

Fig. 4 shows a modification wherein the lowest stratum P of porous concrete is superimposed by an added stratum Q of a strong load-bearing or stone concrete, affording a composite arch or slab having the strength value of stone concrete together with the sound deadening properties of this invention.

The present invention may be usefully embodied in a cellular concrete structure wherein the porosity is produced by the known system of expanding the mix before pouring, for example by introducing bubbles in the form of foam during the mixing operation; and with any system of production of a cellular concrete structure the product may be improved by the mechanical compacting or compressing of the opposite or upper surface, of a floor arch, and the incorporating therein of a layer or sprinkling of added aggregate.

The invention is also applicable to the system of porous concrete production by the introduction into the mix of pellets of a special solid material capable of being removed or driven out subsequently to setting, by volatilization by heat, or otherwise; for example by the so-called Bubblestone system known to the art.

An added advantage, of certain independent utility, in the present invention is its use to afiord a pleasing appearance due todiflusion of waves of light reflected from a ceiling or wall. The workman can produce desirable efi'ects by methodically opening up and exposing the cells, in a manner tosecure both the visual and the acoustic advantages mentioned.

There have thus been described a sound deadening structure and the method of production of the same embodying the principles of the present invention. Since many matters of construction, arrangement, design and procedure may be modified without departing from the principles the invention is not intended to limit the invention to such matters except to the extent set forth in the appended claims.

What is claimedis:

1. A concrete boundary structure wherein the concrete is formed with a great number of empty globular cells divided by concrete septums, and wherein the outer surface of the concrete, facing the room, is opened up thereby widely exposing the adjacent tier of cells as domed cavities between dividing septums, and such open cells occupying a large proportion of the total exposed wall area.

2. A self-supporting, load-bearing concrete ceiling structure containing reinforcement and wherein the concrete is of the expanded type formed with a great number of empty globular cells divided by concrete septums, and wherein the lowermost surface of the concrete, facing the room, is opened up thereby widely exposing the adjacent tier of cells as domed cavities between 5 dividing septums, and such open cells occupying a large proportion of the total exposed ceiling area.

3. A load-bearing concrete floor arch structure wherein the lower stratum of the concrete is 10 formed with a great number of empty globular cells divided by concrete septums, and the upper stratum is solid, dense and hard, and wherein the lowermost surface of the concrete, facing the room, is opened up thereby widely exposing the 15 adjacent tier of cells as domed cavities between dividing septums, and such open cells occupying a large porportion of the total exposed ceiling area.

arystructure comprising laying a cellular concrete mix in the form of the structure whereby it will set into formed concrete containing a great number of empty globular cells divided by concrete septums and with an outer skin covering 25 the outer tier of cells, and then, after the structure has substantially set, removing portions of such outer skin in a manner to expose widely the adjacent tier of cells as domed cavities between dividing septums. 5. The method of producing a cellular concrete wall structure comprising laying a self-expanding cement mix in the form of the structure whereby it will expand and set into a formed concrete containing a great number of empty globular cells 35 divided by concrete septums and with an outer skin covering the outer tier of cells, and then removing portions of such outer skin in a manner to expose widely the adjacent tier' of cells as domed cavities between dividing septums.

FRANCIS P. SLOAN.

4. The method of producing a concrete bound- 20" 

